The invention relates to an exhaust system of a multi-cylinder reciprocating piston engine of the general type is described in the German Patent Document DE-OS 24 01 287. In order to avoid an overheating of the catalyst, air is blown into its outer jacket above a certain exhaust gas temperature. The air, which originates from a compressed-air source, by way of a change-over valve, on one side, flows into the outer jacket of the catalyst, flows along the outside of the catalyst monolith and, behind the monolith, mixes with the exhaust gas flowing out of it. In this manner, the oxidation of the exhaust gas is promoted. The introduction of air on one catalyst side may have the result that the catalyst bends as a result of a "cold-temperature shock" and becomes inoperative.
It is an object of the invention to develop an exhaust system of this type such that the catalyst suffers no damage as a result of the introduction of the air and an effective afterreaction of the exhaust gases is achieved.
This object is achieved according to the invention by providing an exhaust system for a reciprocating piston engine, comprising;
an exhaust pipe,
catalyst mean inserted in the exhaust pipe,
and air feeding line means for feeding outside air to the catalyst mean for facilitating afterreaction of exhaust gases flowing through the catalyst means,
wherein the catalyst means include two separate monoliths enclosed by a common outer jacket,
and wherein the air feeding line means is disposed to have an air feeding point in between the two separate monoliths.
If the air feeding point is situated approximately in the center between two separately manufactured monoliths which are enclosed by an outer jacket of the catalyst, the air can flow into the catalyst without subjecting it to the risk of damage as a result of an excessive cooling. By means of the additional constructive measures disclosed in the illustrated preferred embodiment, this risk is reduced to the extent that the operating reliability of the catalyst is ensured in all possible operating conditions of the engine and at the same time, a reasonable manufacturing of the catalyst is ensured.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.